Thermostatic switch



Feb. 9, 1943. A D KENE v2,310,7'91

THERMOSTATIC SWITCH Filed Dec. 51, 1940 Patented Feb. 9, 1943 UNITED sTATEs PATENT oFFlcE TnEnMos'rA'rIc SWITCH Alvin D. Keene, Rochester, N. Y., assigner to Samson United Corporation, Rochester, N. Y., a corporation of Delaware Application December 31, 1940, Serial No. 372,599

2 Claims.

This invention relates to thermostatically op- -erated electric switches with vVariable heat conadjustable vmovement limiting means with whichv an open switch position may be secured and maintained at any desired temperature of the electrically heated device by the movement of the variable heat control, regulating member to a predetermined off position.

. This and other objects of this invention will become more readily apparent from the detailed description thereof which follows, reference being had to the accompanying drawing in which- Figure 1 is a longitudinal sectional view of an electric atiron 'embodying my novel electric switch construction.

Figure 2 is a vertical crosslsection taken on the line 2-2 of -Figure 1.

Figure 3 is a detail longitudinal sectional view of a modified form of my novel electric switch construction.

Figure 4 is a detail longitudinal sectional view of a modified form of my novel electric switch construction.

The switch structure, forming the subject matter of my present invention, may be used for any thermostatically controlled electrically heated apparatus and is shown in connection with an electric iiatiron for illustrative purposes only. The thermo-responsive member I is fastened with one end to the sole plate 2 which is heated by the electric heating unit in the body member 3. The latter is supported on the sole plate and a hood 4 is placed over it with a handle 5 atta'ched theretovfor the handling of the iron. The switch structure which controls the electric current for the heating of the iron is mounted on the'body member 3 which, for this purpose, is provided with the recess 6 above the thermo-responsive member I.

The form of the switch illustrated in the 11gures of the drawing comprises a saddle member` I which carries the ears 8, 8 for the attachment thereof to the body member'3 on each side o! the recess 6. Pivotally mounted between the sides of the saddle member is the rocker arm 9 which carries the flexible switch arm III and the rigid switch-arm II. A terminal in the form of the plate IIIA contacts the arm Ill.I Another terminal IIA 'is provided by a rearward extension of the arm II. The switch arms and their terminals are electrically insulated from each (ci. 20o-iss) sheets I2, I2. The switch arms carry the contact buttons I3 and I4 which are yieldingly held in Contact with each other by the switch arm I0 which, for this purpose, is normally held flexed to provide the yielding Contact between the contact buttons.

At the 'outer free end the flexible switch arm II) carries the operating member I5 which is made up of a suitable electric insulating material such as porcelain. This operating member projects above and below the switch arm I 0, and in the upper portion, above the switch arm I0, is provided an opening IB. Projecting into this opening is an adjustable stop I1 which is oiset from the end of the spring member I8. The latter is anchored to the underside of the saddle member 'I and an adjusting screw I9 is threaded thru the saddle member to flex the spring member and -adjustably position the stop Il in the opening I6 of the switch arm operating member I5. A

A spring 20 yieldingly urges the rocker arm 9 against the adjusting screw 2l. For this purpose one end of the spring 20 is `anchored to the top of the fixed saddle member l while its other end is attached to and exerts its pressure against the rocker arm 9 to yieldingly force its forward end against the adjusting screw 2I. Movement of the adjusting screw by means of its pointer handle 22 is thus adapted to swing the rocker arm up or down for positioning of the switch arms relative to the thermo-responsive member I located below them.

As illustrated in Figure 3, the pointer handle 22 is supplemented by a setting scale 23 which, instead of indicating the actual temperatures which will be maintained with the pointer handle at given points on the scale, indicates the kind of material which can be ironed at the predetermined temperatures provided by the automatic operation of the switch by the thermo-responsive member. The thermo-responsive member fiexes upwardly as it responds to the heat 1 vof the sole plate 2 and in so doing the outer free end engages and raises the operating member I5. This in turn exes the switch arm I0 to move its Contact button I3 out ofv contact with the contact button i4 of the switch arm II. The electric circuit which passes thru the switch arm for the operation of the heating units of the iron is thus opened and closed by increases and decreases of the temperature ofthe sole plate which cause the thermo-responsive element to ilexv back and forth to open and close the elecother and the rocker arm t* by means of theI mica tric circuit for the maintenance of the desired temperature of the sole plate. The position o! l the adjusting screw, as indicated by the pointer handle on the setting scale, thus operates to of the pointer handle to this off position theadjusting screw`2| operates to swing the rocker arm 9 to jointly move both the switch arms l0 and toward the sole plate until movement of the switch arm I is arrested bythe engagement of the stop |1 with the upper edge of the opening I6 in the operating member-|5. Continued movement of the adjusting screw thereafter into the off position of the pointer handle causes the rigid switch arm to be forced away from the exible switch arm and separates the contact buttons I3 and Il to open the electric circuit thru them.

AS above pointed out, the stop I1 is adjustable by meansof the adjusting screw I9 and its position may thus be accurately set for the opening of the switch at any temperature of the iron by placing the pointer handle in the o position indicated on the setting scale. The automatic operation of the thermostatically operated switch is thus supplemented by a manual operation into its oi position to eliminate the use of a separate switch for completely shutting off the iron,

In the modined form of switch construction illustrated in Figure 4, both of the switch arms 3|| and 3| are yielding and are suitablyl anchored to the underside ofithe bracket 32 for yieldingmovement relative thereto. The free end of the switch arm 30 carries the contact button 30A while. the hook shaped free end of theswitch arm 3|, which extends around the end of the switch arm 30, carries the contact button 3|A. A movement limiting member 33 of suitable electric insulating material similar to the member I in the switch structurein Figure 2, is carried by the switch arm 3| and the adjustable stop 34 extends into the opening in the member 33 to normally hold the switch arm in a properly adjusted normal position in which the contact .button 30A contacts the contact button 3|A.

Switch arm 30, which carries the contact button 30A, is operated by the adjusting screw 35 which has threaded engagement with the sleeve 36. Ihe latter is rotated by the dial member 31 and is suitably journaled in the bracket 32. The adjusting screw carries an arm 38 which engages into a slot 39 in the bracket 32 to keep'the adjusting screw from rotating and thus provide an endwise movement thereof. In this way rotation of the sleeve 36 by the dial member causes the adjusting screw to be threaded inor out of the sleeve for the movement of the switch arm 30 relative to the switch arm 3| The operation of the switch is as follows: For the automatic opening of the switch at a predetermined temperature the dial member is turned to a position in which it indicates on the dial plate the desired temperature' of the type of material which can.. "monedgat that temperature. Movement of the dial member in one direction causes the adjusting screw to move and raise the switch arm 30 and allows the switch arm 3| to follow into a joint position in which the thermostatic member operates to separate the contact buttons 30A and 3|A by separately raising the switch arm 3| at the indicated temperature. Movement of the dial member in the opposite direction causes the adjusting screw to move the switch arm 30 downwardly and the switch arm 3| will follow this movement until its downward movement is arrested by the stop 34. Further downward movement. of the switch arm 30 by the adjusting screw thus separates the contact button 30A and 3|A to positively open the switch. This takes place when the dial member 31 is turned into the oi position indicated on the dial plate.

From the foregoing it will be apparent that the switch illustrated in Figure 4 functions substantially the same as the switch illustrated in Figures 1 to 3, inclusive, in that it may be set for automatic operation by the thermo-responsive member by placing the dial member into various positions within a predetermined range of movement indicated on the dial plate and may be operated manually by placing the dial member into a predetermined position outside of this predetermined range of movement.

I claim: y

1. In a switch for operation by a thermoresponsive' member, the combination of a switch support, a rocker member mounted to swing on said switch support, spring means interposed between said rocker member and said switch support for movement of said rocker member in one direction, adjustable setting means carried by said switch support for movement Yof said rocker member inthe opposite direction,

va pair of switch members carried by said rocker member in yielding contact with each other for joint movement with said rocker member, a movement limiting member carried by one of said switch members, stop means on said switch support for engagement of said movement limiting member to limit the joint movement of said switch members by said spring means in'one direction and limit the movement of the switch member carrying the movement limiting member in its movement with the other switch member in the opposite direction.

2. In a thermostat operated switch, the combination of a pair of yieldingly contacting switch members, a thermo-responsive member located relative to said pair of switch members, adjustable setting means for collectively moving said pair of switch members relative to said thermoresponsive member for operationof one 'of said switch members by said thermo-responsive member, stop means for limiting the movement of the last mentioned switch member comprising an electric insulating member having a hole therethru carried by said last mentioned switch member, and a iinger extending into said hole 

